WASHINGTON (AP) - Charging that Vice President Dick Cheney contributed to a 2002 die-off of about 70,000 salmon near the California-Oregon border, House Democrats planned a hearing Aug.7 to explore his intervention in the Klamath River Basin.

But some House Republicans say the hearing in the Natural Resources Committee could upset negotiations to end years of battling over the region, where drought in 2001 led to a cutoff of irrigation water - and then a diversion to help farmers.

That diversion, directed in part by Cheney, resulted in the largest adult salmon kill in the history of the West, Democrats say.

At the very least, Cheney's actions to help farmers at the expense of threatened fish demonstrated the Bush administration's penchant to favor politics over science in the implementation of the Endangered Species Act, said Rep. Nick Rahall, D-W.Va., chairman of the Natural Resources panel.

Republicans counter that there is no evidence Cheney did anything improper and say the evidence doesn't support blaming his actions for the fish kill.

In 2004, the Interior Department's inspector general found no basis for a claim by Democratic presidential candidate John Kerry that White House political advisers interfered in developing water policy in the Klamath.

Republican Reps. Wally Herger and John Doolittle of California and Greg Walden of Oregon say the hearing couldreopen wounds even as farmers, fishermen, Indian tribes and environmentalists near solutions to the regional water woes.

While arguments are expected on all sides, one person who won't be adding to the din is Cheney.

A spokeswoman said Monday the vice president - who as a Wyoming congressman served on the committee - will not be attending the hearing.

Rahall denied GOP claims that the hearing is a politically motivated witch hunt.

As I said when I became chairman ... back in January, I am committed to conducting vigorous oversight - a constitutional duty that this committee largely neglected in recent years, Rahall said in a statement. Repeated troubling reports that political considerations are trumping scientific facts in the implementation of the Endangered Species Act ... constitute just one area in a long line of problems plaguing the Interior Department that deserve scrutiny by the Congress.

Herger, whose district includes California agricultural areas irrigated by the Klamath project, said it was only proper for Cheney and administration officials to be involved in developing a 10-year water plan for the Klamath River. Courts later called the plan arbitrary and in violation of the Endangered Species Act.

Court battles are continuing over how to divide scarce water among farms, fish, Indian tribes and other users, but groups in the region say they hope to work out a deal by fall to settle many of the issues - including whether to remove four dams on the Klamath River to increase salmon spawning habitat.

We continue to be encouraged by what we are hearing of these ongoing efforts by traditional adversaries to reach a longterm solution to the problems of the Klamath Basin, Herger and other GOP lawmakers wrote in a letter to Rahall.

While they may not agree with all aspects of the ultimate solution, we support and endorse their efforts to finally put their differences aside and move beyond the political and policy conflicts of the past, the GOP House members wrote. Continued political conflict and rhetorical attacks accomplish nothing but perpetual gridlock and bitterness.

Meanwhile, commercial fishermen in Oregon and California held a conference call Monday to tell personal stories of economic hardship, which several said was connected to Cheney's 2002 actions. Commercial fishing in the two states was cut by more than 90 percent last year - the largest commercial fishing closure in the history of the country - resulting in more than $60 million in damage to coastal economies.

In all my years I've never seen it so tough as it has been these last couple of years, said fisherman Larry Collins of San Francisco. People don't have the money to do boat maintenance, they can't keep up on insurance. I've never seen it so bad as it is right now in the fleet, and in the last six years with these kinds of immoral environmental decisions made by this administration.